/*-
 * ============LICENSE_START=======================================================
 * SDC
 * ================================================================================
 * Copyright (C) 2017 AT&T Intellectual Property. All rights reserved.
 * ================================================================================
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * ============LICENSE_END=========================================================
 */
package org.openecomp.sdc.vendorsoftwareproduct.services.schemagenerator;

import freemarker.cache.StringTemplateLoader;
import freemarker.template.Configuration;
import freemarker.template.Template;
import freemarker.template.TemplateExceptionHandler;
import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import org.openecomp.core.utilities.applicationconfig.ApplicationConfig;
import org.openecomp.core.utilities.applicationconfig.ApplicationConfigFactory;
import org.openecomp.core.utilities.applicationconfig.type.ConfigurationData;
import org.openecomp.sdc.common.errors.CoreException;
import org.openecomp.sdc.common.errors.ErrorCategory;
import org.openecomp.sdc.common.errors.ErrorCode;
import org.openecomp.sdc.vendorsoftwareproduct.types.composition.CompositionEntityType;
import org.openecomp.sdc.vendorsoftwareproduct.types.schemagenerator.SchemaTemplateContext;

public class SchemaGeneratorConfig {

    public static final String SCHEMA_GENERATOR_INITIALIZATION_ERROR = "SCHEMA_GENERATOR_INITIALIZATION_ERROR";
    public static final String SCHEMA_GENERATOR_INITIALIZATION_ERROR_MSG = "Error occurred while loading questionnaire schema schemaTemplates";
    private static final String CONFIGURATION_NAMESPACE = "vsp.schemaTemplates";
    private static Map<SchemaTemplateId, SchemaTemplate> schemaTemplates = new HashMap<>();
    private static ApplicationConfig applicationConfig = ApplicationConfigFactory.getInstance().createInterface();
    private static Configuration configuration = new Configuration(Configuration.VERSION_2_3_23);
    private static StringTemplateLoader stringLoader = new StringTemplateLoader();

    static {
        configuration.setClassLoaderForTemplateLoading(SchemaGenerator.class.getClassLoader(), File.pathSeparator);
        configuration.setDefaultEncoding("UTF-8");
        configuration.setTemplateExceptionHandler(TemplateExceptionHandler.RETHROW_HANDLER);
        configuration.setLogTemplateExceptions(true);
        configuration.setTemplateLoader(stringLoader);
    }

    public static void insertSchemaTemplate(SchemaTemplateContext schemaTemplateContext, CompositionEntityType entityType,
                                            String schemaTemplateString) {
        applicationConfig
            .insertValue(CONFIGURATION_NAMESPACE, new SchemaTemplateId(schemaTemplateContext, entityType).toString(), schemaTemplateString);
    }

    /**
     * Gets schema template.
     *
     * @param schemaTemplateContext the schema template context
     * @param entityType            the entity type
     * @return the schema template
     */
    public static Template getSchemaTemplate(SchemaTemplateContext schemaTemplateContext, CompositionEntityType entityType) {
        SchemaTemplateId id = new SchemaTemplateId(schemaTemplateContext, entityType);
        ConfigurationData configurationData = applicationConfig.getConfigurationData(CONFIGURATION_NAMESPACE, id.toString());
        SchemaTemplate schemaTemplate = schemaTemplates.get(id);
        if (schemaTemplate == null || schemaTemplate.timestamp != configurationData.getTimeStamp()) {
            stringLoader.putTemplate(id.toString(), configurationData.getValue());
            Template template;
            try {
                template = configuration.getTemplate(id.toString());
            } catch (IOException exception) {
                throw new CoreException(
                    new ErrorCode.ErrorCodeBuilder().withCategory(ErrorCategory.APPLICATION).withId(SCHEMA_GENERATOR_INITIALIZATION_ERROR)
                        .withMessage(SCHEMA_GENERATOR_INITIALIZATION_ERROR_MSG).build(), exception);
            }
            schemaTemplate = new SchemaTemplate(template, configurationData.getTimeStamp());
            schemaTemplates.put(id, schemaTemplate);
        }
        return schemaTemplate.template;
    }

    private static class SchemaTemplateId {

        private SchemaTemplateContext context;
        private CompositionEntityType entityType;

        public SchemaTemplateId(SchemaTemplateContext context, CompositionEntityType entityType) {
            this.context = context;
            this.entityType = entityType;
        }

        @Override
        public String toString() {
            return context + "." + entityType;
        }

        @Override
        public boolean equals(Object obj) {
            if (this == obj) {
                return true;
            }
            if (obj == null || getClass() != obj.getClass()) {
                return false;
            }
            SchemaTemplateId that = (SchemaTemplateId) obj;
            if (entityType != that.entityType) {
                return false;
            }
            if (context != that.context) {
                return false;
            }
            return true;
        }

        @Override
        public int hashCode() {
            int result = entityType != null ? entityType.hashCode() : 0;
            result = 31 * result + (context != null ? context.hashCode() : 0);
            return result;
        }
    }

    private static class SchemaTemplate {

        private Template template;
        private long timestamp;

        public SchemaTemplate(Template template, long timestamp) {
            this.template = template;
            this.timestamp = timestamp;
        }
    }
}
